On 04/18/2019 10:28 AM, Peter Zijlstra wrote: > On Sat, Apr 13, 2019 at 01:22:58PM -0400, Waiman Long wrote: >> +#ifdef CONFIG_X86_64 >> +#define RWSEM_MERGE_OWNER_TO_COUNT >> +#endif >> +#ifdef RWSEM_MERGE_OWNER_TO_COUNT >> + >> +#ifdef __PHYSICAL_MASK_SHIFT >> +#define RWSEM_PA_MASK_SHIFT __PHYSICAL_MASK_SHIFT >> +#else >> +#define RWSEM_PA_MASK_SHIFT 52 >> +#endif > I really dislike how this hardcodes x86_64. > > It would be much better to have a CONFIG variable that gives us the > PA_BITS. Then all an architecture needs to do is set that right. > > FWIW: > > arch/arm64/Kconfig:config ARM64_PA_BITS_48 > arch/arm64/Kconfig:config ARM64_PA_BITS_52 > > So ARM64 could also use this -- provided we get that overflow thing > sorted.
That will work too. I just a bit hesitant to add new config variable. Cheers, Longman
